Simulation of Tunneling States in Random-Network Glasses

Abstract

Fully automatic computer simulation of random-network structures in amorphous Si and Ge has been achieved using a generalization of Keating's potential. The local potential for one-atom displacements shows many multiple minima with broad distributions of the energy difference and tunneling matrix element. These distributions lead to reasonable estimates for the specific heat, which behaves as $T\mathrm{ln}T$. One-atom tunneling states appear to be appropriate for amorphous Si/Ge.